Conventional transport systems used in industry for moving articles from one location to another typically comprise rotary dive systems having mechanical components such as gears, shafts, keys, sprockets, chains and belts, rollers, and the like for moving an axis or transport element (such as a conveyor belt) that transports articles along a predetermined path or track. The rotary drives are controlled using a computer control system that operates control software to permit an operator to enter into the control system various command parameters that are used to create a motion profile for the transport element being utilized by the particular transport system.
Transport systems, such as controlled motion systems utilizing linear drives, are used in a wide variety of processes (e.g. packaging, assembly automation, processes involving use of machine tools, etc.) and provide the advantage over conventional rotary drive systems of increasing both the speed and the flexibility of the process. In particular, linear motors operate as magnetic drives creating a changing magnetic field to directly transport the axis or transport element along a defined track, thereby eliminating various conventional axes, such as gear heads, shafts, keys, sprockets, chains and belts, used with traditional rotary drive systems. The reduction of mechanical complexity over rotary drive systems provides both reduced cost and increased speed capability by virtue of reduced inertia, compliance, damping, friction and wear. Further, controlled motion systems utilizing linear drives also provide greater flexibility than conventional rotary drive systems by allowing one or more individual axes or transport elements to be independently controlled while transporting articles along an entire track.
Unlike conventional rotary drive systems that have a single drive for energizing an axis or transport element for moving articles along a track, linear motion systems typically comprise interconnected track sections wherein one or more drives are electrically coupled to a plurality of transport elements and have individually controlled coils that cooperate with one or more control units to energize or de-energize the coils to create magnetic fields effective for providing controlled motion of each transport element traveling along the track. Such systems also employ a plurality of linear encoder readers spaced at fixed positions along the track and sensors mounted on each transport element that cooperate with the linear encoder readers to provide signals to a control unit for use in determining the position of each transport element along the track.
Typically, control architecture utilized for conventional linear motion transport systems include an input device, such as a keypad, whereby an operator enters command parameters (such as the particular track identification, the speed that a transport element or axis travels along the track, stop and start locations, and time parameters for the transport element) into a control unit, such as a convention computer system, to create a motion profile. The control unit functions to operate software specifically designed for controlling the operation of the particular linear transport system being used. Unfortunately, the use of such specifically designed software for controlling a particular linear motion transport system often requires the operator to learn new software protocols for each new designed software package. Thus, for example, an operator using a plurality of different transport systems must learn to operate a number of different software packages.
Conventional control systems are typically designed for transport systems where transport elements do not move from one drive section to another dive section, such as when transport items are traveling along different tracks or move from one track to another track. Accordingly, a need exists for control architecture that can control transport elements moving from one drive to another drive, such as linear motion systems when a transport element moves from traveling along one track to traveling along another track or when it is desirable to control transport elements traveling along different tracks using a single control system.
Another problem often encountered with the use of specifically designed control software is that it is often desirable to have a transport system of one manufacturer coupled to the same control system being used by a transport system of another manufacturer. Accordingly, such a combined system eliminates the need for an operator to use two different control software packages thereby decreasing the cost and complexity of the transport systems. Further, the use of transport systems from different manufacturers often requires the operator to use more than one control system (or software package) or learn the operation of different software packages thereby increasing the training time for the operator and decreases the efficiency of the overall operation. In addition, the difficulty of integrating two different transport systems having two different control systems significantly increases the complexity and cost of the overall operation.
Accordingly, it is desirable to have a control architecture effective for controlling a transport system that has similar programmatic features as used in conventional single drive systems, such as rotary drive systems. It is also desirable to have control architecture effective for controlling a transport system that allows an operator to use traditional software for controlling conventional single drive transport systems; that can be used to control a transport system having more than one drive system; that can be used with linear drive systems whereby transport elements operate on different tracks; that allows additional independent drive systems to be easily incorporated into the transport system; allows a single control system to operate more than one transport system or a transport system having more than one track; and allows an operate to use traditional control software for a transport system having a single transport element for controlling a transport system having more than one transport element.